Pneumatic action



. March 27, 1928. 1,664,041

J. S. MAXWELL PNEUMATIC ACTION Filed Aug. 25, 1925 avwentoz J hn .5,Maxwell.

Patented Mar. 27, 1928.

UNITED STATES 1,664,041 PATENT OFFICE.

JOHN S. MAXWELL, OF RICHMOND, INDIANA, ASSIGNOR TO STARR PIANO COMPANY,

OF RICHMOND, INDIANA, A CORPORATION OF INDIANA.

PNEUMATIC ACTION.

Application filed August 25, 1925/ Serial No. 52,309.

This invention relates to pneumatic player pianos and similar musicalinstruments, and refers more particularly to valves for pneumaticactions.

The object of this invention is to produce a valve which is of lightconstruction so as to be susceptible of having its position changedimmediately whenever there isa variation of pressure on its diaphragm,and which will, at the same time, be capable of seating firmly on itsseat even though its stem be inclined at an angle from the plane of thevalve seat orthat the same is unlikely to be seated tightly for anyother cause, such as, for example, an inclined valve seat.

The valve seats in the actions are pressed or threaded into place, andit is probable that some of these might not assume the exact trueposition intended, that is,'of having its seat in a horizontal planeperpendicular to the natural position of the valve stem. In such a case,if the valve and valve stem were rigidly connected, binding might resultand the general efliciency of the instrument couldbe seriouslyafi'ected. Binding, however, would not occur in the usual case, but alack of complete seatin of the valve on its seat might result,whicfiwould allow a leakage of air that would entail the expenditure ofmore power than should be necessary in the operation of the piano.

Heretofore, valves have been used that would allow for a universaladjustment and flexible connection between a valve stem and valve thatwould permit the valve to seat truly even though the seat be at an anglewith the horizontal and the valve assume ing due to any rotarydisplacement, and it is part of my purpose of invention, as outlinedabove, to produce a simple form of valve capable of universal adjustmentbe tween the valve and valve stem with a minimum number of parts andamount of material which will possess the desired qualities of lightnessand flexibility and be capable of effective sealing.

Other objects and uses of the invention will appear from a detaileddescription of the same, which consists in the features of constructionand combinations of parts hereinafter described and claimed.

In the drawings,

Fig. 1 is a transverse fragmentary view of an action showing the valvein its normal position.

Fig. 2 is a pers ective view from the under side of the va ve.

Fig. 3 is a section of the valve and valve stem.

In Fig. 1 the valve is shown in its normal position in an action, and itcomprises a disk or head 10 having a projection 11 extending from itsupper surface and passing through a facing 12 of leather, fiber, orother suitable material. The lower face of the disk has raised from itscenter, or integral therewith, a button 13. To the lower face is gluedor otherwise caused to adhere another facing 14.- which extends over andcovers the button forming a smooth rounded rise at the center, Fig. 2.The stem of the valve may be of any design and the one which I havechosen to illustrate has a central portion 15 which has a cross-sectionof slightly greater area than the button on the disk, but it isdesirableonly that these two features have approximately the same area.Four flanges 16 extend radially from the central portion 15 of the stem,but any other arrangement could be used. In assembling the valve andvalve stem the central portion of the top of the stem is glued directlyto the leather facing on the lower surface of the valve in such aposition that the center of the button is in alignment with the axis ofthe stem. It is evident that, owing to the height of the button from thevalve face and its hemispherical contour, the stem will be susceptibleto being inclined in any direction from the perpendicular or, in otherwords, from a normal to the plane of the valve face.

Another essential and most desirable feature is to have some amount offlexibility and springiness between the stem and the valve as well asuniversal adjustment, and I have obtained excellent results in thisdirection by gluing the leather facing on the lower side of the valve atits edges only and not having any close adherence between the button orthe face immediately surrounding the button with the facing. Thiscondition allows for pivotal motion of the stem in respect to the valvewithout any tendency to cause a separation of the stem from the leatherfacing, Fig. 3. When the stem is at an angle with the valve the leatheron one side of the button may be slightly lifted from contact with thevalve face, but the main contacting glued area will not be disturbed.

I have used leather as a facing because of its excellent sealingqualities due to its pliability and consequent ability to settle andfill any irregularities in the valve seat, and also because it does awaywith the necessity of having any other cushion or resilient connectionbetween the valve and the stem. The leather lends itself to suchalternate stretching and compressing during the operation of the valveas it may be called upon to submit to, but I do not wish to be limitedto this material since any other material capable of performing the samefunction could be used.

The valve is shown in its normal position on seat 17. When a hole in themusic roll passes over the opening in the tracker bar related to anyparticular action, air is admitted to chamber 18 and the resultingunbalanced pressure on diaphragm 19 causes the valve to be raised sothat its upper facing 12 contacts the valve cap 20 and closes the port21 thereby shutting off communication with the atmosphere of passage 22and causing the bellows to collapse and actuate the note striking arm inthe manner well known in the art. 7

The diaphragm 19 comprises a normally dish-shaped member of lightconstruction which may be made of rubber, fibre, leather, or of anyother air tight flexible material. It has a flanged edge 23 which bearsupon and is secured to ledge 24- and when the diaphragm is in aposition'of rest, its central portion extends downwardly within a recessor chamber. To the central portion of the diaphragm is attached apressure distributor or equalizer 25 in the form of a disk andpreferably made from a single piece of material so as to insure rigidityand simplicity as well as lightness. At the center of the pressuredistributor there is a rounded projection in the form of an indentation26 the lowest extent of the outer surface of the projection of which isattached to the diaphragm by means of glue, cement, a pin, or

otherwise fastening. -The rounded surface allows for tilting movement inany vertical plane between the pressure distributor and the diaphragm sothat the upper surface of the distributor will seek the plane of thelower end of the valve stem when the diaphiagm is raised by air"pressure. This action will occur even though the valve stem be very muchinclined from its normal vertical position. In order to cushion thecontacting effort of the valve-stem and pressure distrilimtor, a thincushion 27 of soft fibrous material is secured to the pressure distributor at its center. It is-of larger dimension than the largestcross-sectional dimension of the valve-stem, and is suflicient-ly thinthat a space remains between it and the valve-stem when the parts are inthe positions illustrated in Fig. 1.

It is evident from the foregoing description that the connection betweenthe valvehead and the valve-stem, and the relation of the valve-stem tothe pressure distributor, and the connection between the pressuredistributor and thediaphragm, are such as to insure perfect and instantoperation of the pneumatic due to the universal adjustability of thevalve parts, the lightness and simplicity of their construction, andtheir mechanically efliciont design which permits of complete seatingand accurate registry of the. correlated parts.

These improvements are susceptible to variations in structure and shape,and I do not wish to be limited to the particular form described, for Icontemplate the use of other suitable materials than those recited,-andsuch alterations and modifications as may be deemed expedient and comingwithin the scope of the appended claims.

What I claim is" 1. A valve comprising a head, a stem, and a resilientfacing intermediate said head and stem, said head having a projectiondirectly above said stem. I

2. A valve comprising a head having a raised portion at its center, afacing cut-ending over said raised portion, and a. stem. Elf". fixed tosaid facing opposite said raised portion.

3. A valve comprising a. head having a raised portion at its center, afacing extending over the surface of said valve and said raised portion,and. a stem afiined to the out or surface of said facing at a pointopposite said raised portion.

l. A valve comprising a head having a raised portion at its center andintegrally. therewith, a facing secured to the valve face around saidraised portion and overlying said raised portion, and a stem affixed tothe outside surface of said facing opposite said raised portion. r

5. A valve comp-rising a head having a raised portion, afacing affixedto the surface of said valve so as to allow parting-of said valve andfacing at a. definite place, and a. stem secured to the outer surface ofsaid facing opposite said definite place.

6. A valve comprising a disk having a substantially hemispherical buttonprojecting from its surface, a facing extending over said button andsurface, and a stem at fixed to said facing opposite said button, saidlstem having a. cross-sectional end surface of relatively greater areathan said button.

7. A valve comprising a disk having-1a substantial hemispherical buttonprojecting from its surface, a facing extending over said button andaffixed to the surface around said button, and a stem. having one endaffixed to said facing opposite said button whereby said stem may betilted in respect to said disk.

8. In an action for player pianos, the combination of a valve comprisinga head, a stem, a pressure distributor having a projection at itscenter, and a diaphragm secured to said pressure distributor.

9. In an action for player pianos, the combination of a. valvecomprising a head, a stem, a facing connecting said valve and stem, apressure distributor having a projection, a diaphragm secured to saidpres sure distributor at the highest point of said projection, and meansintermediate said stem and pressure distributor for cushioning theeffort of impact.

10. In an action for player pianos, the combination of a valve, a buttonon said valve, a facing overlying said button and forming the soleconnect-ion between said stem and said valve, and a diaphragm dis.-posed at the opposite end of said stem and spaced therefrom.

11. In an action for player pianos, the

combination of a valve, a stem flexibly connected to said valve, adiaphragm, a. pressure distributor flexibly connected to said diaphragmand spaced from said stem, the flexible connection permitting ofrelative rocking motion of said. disk and pressure distributor.

12. In an action for player pianos, the combination of a valve, a stemflexibly connected to said valve, a disk having a rounded projectionintegral therewith, a diaphragm secured to said projection so as topermit tilting between said diaphragm and said disk, and means on saiddisk for contacting the end of said stem.

13. A valve comprising in combination a head, a stem, an actuatingdiaphragm, and a disk spaced from said stem and independent thereof andsecured to said diaphragm at a single point of less area than the areaof said disk.

14. A valve comprising in combination, a

head, a stem, an actuating diaphragm, and a disk having a raised portioncontacting said diaphragm, said disk being intermediate said diaphragmand! said stem and free from connecting relation with said stem.

In testimony whereof I hereto afiix my signature.

- JOHN S. MAXWELL.

